Imaging of objects with high magnification and large view area at small scale is desirable in many applications, such as micro defect detection, precise manipulation, and in-situ material characterization. Microscopic imaging techniques are one of the suitable techniques for these applications. This is because microscopic imaging apparatuses can image micro- or nano-sized sample objects with resolution up to nanometer scale, and by moving the sample stage and image the sample object at different positions on the same plane, a large microscopic view area can be obtained.
Despite these advantages, most of the existing microscopy systems can only image from one fixed direction. And as a result, some other surfaces of the sample object are not imaged, which results in loss of information. More importantly, the information obtained from a single surface is usually not complete and hence cannot fully reflect the overall properties of the object.